Device and device for treating aqueous liquids in human medical treatment

ABSTRACT

The invention relates to a method for treating liquids, especially dialysis liquids, for purposes and for the elimination of harmful substances contained therein. The liquid is exposed to a UV radiation in the presence of physically dissolved oxygen, and is guided along the surface of a UV radiator in the form of a chaotic flow column or a thin surface film.

The invention relates to a method for treating liquids, especiallydialysis liquids, for the purpose of sterilization and elimination ofharmful substances contained therein, wherein the liquid is exposed to aUV radiation in the presence of physically dissolved oxygen.

For the purpose of human medical treatment where the patient directly orindirectly comes in contact with water or aqueous solutions, anextremely high purity of the water is an absolute necessity. However, anadequate water treatment is frequently not possible in practicaloperations because of a lack of technical means for realizing it. Anadequate water treatment in this case refers to the elimination ofproblematic micro-organisms (germs, funguses, etc.) and pyrogenic agents(endotoxins, exotoxins), wherein harmful substances such as pesticidesand the like must also be mentioned. This is particularly true fortreatments requiring several liters of flowing aqueous liquids where thewater for the treatment is drawn from the available municipal watersupply without first being adequately treated. One example to bementioned in this connection is the haemodialysis of patients sufferingfrom kidney disease.

At the present time, the production of so-called “ultrapure waterdialysate” for the above-described practical use is possible only whenusing a sterile filter in combination with an activated carbon filter.However, this treatment step is very cost-intensive and does not offer asatisfying solution over the long term due to the forming ofmulti-resistant germs. Even though physicians expressly demand ultrapuredialysate, it is not possible to provide it in every case at this pointin time.

The theoretical options, known from literature, for UV-ray disinfectionin principle provide alternatives to using a sterile filter for thepurpose of treating the water for human medical treatments. It is knownthat the UV disinfection is suitable for sterilization as well as forproducing so-called “ultrapure water” under certain conditions.Ultrapure water is used, for example, in the semiconductor industry anddistinguishes itself by an extremely small share of carbon compoundsbesides having the properties of highly purified water. During thesterilization with UV rays, living micro-organisms are killed orinactivated by destroying the DNA with a wavelength of λ=254 nm. Inaddition, further harmful substances and endotoxins can be decomposedwith the aid of UV rays and/or oxidative processes, which are triggeredand maintained with the aid of ultrasound, in an interaction with the UVrays, such that they are no longer damaging to the human organism.

At the present time, no device or method based on the UV sterilizationand oxidative processes generated in an interaction exists which makesit possible to produce ultrapure water. That is to say no device ormethod for killing micro-organisms, eliminating pyrogenic agents anddecomposing harmful substances under dynamic conditions, meaning severalseconds before the patient comes in direct or indirect contact with thewater.

With the present invention, a device and a method have been developedfor the first time for producing ultrapure water under dynamicconditions. The invention thus makes it possible to produce ultrapurewater during a limited time interval that depends on the respective typeof treatment, without requiring additional chemical additives orcost-intensive auxiliary means. As a result, these treatments arequalitatively raised to a noticeably higher level, which not onlyincreases the quality of life for the patient, but in some circumstancescan also be a life saver.

The present state of the technology does not disclose any device ormethod for solving this problem. Known methods only permit realizingseveral partial aspects of a water treatment, such as:

-   1. Sterilization of flowing liquids with UV rays of the wavelength    λ=254 nm.-   2. Decomposition of hydrocarbons in flowing liquids, using the    wavelength λ=185 nm in combination with additional methods (no    specifics from the manufacturer).-   3. Sterilization and oxidation of organic substances with UV rays of    the wavelength λ=254 nm and by adding OH⁻ radical generators such as    hydrogen peroxide and ozone.-   4. Generating of radicals through irradiating of titanium dioxide    with λ=360 nm for disinfecting static systems such as surfaces.-   5. Xenon lamps which are still in the developmental stage and are    not yet commercially available for generating UV rays with a    wavelength of λ=170 nm for cleaving H₂O into H and OH. The    sterilizing effect of this wavelengths is no longer a given.

It is the object of the present invention to produce sterile andendotoxin-free water or aqueous solution under dynamic conditions withthe aid of UV rays for use in human medical treatment and in the foodindustry. In particular, the object is to produce an “ultrapuredialysate,” having a flow rate ranging from 0 ml (static) to at least10,000 ml/min and, preferably, for producing infusions with the onlinemethod.

The invention furthermore relates to a method for treating liquids, inparticular dialysis liquids, for the purpose of sterilization andelimination of harmful substances contained therein, wherein the liquidis exposed to a UV radiation in the presence of physically dissolvedoxygen and wherein the liquid is guided along the surface of a UVradiator in the form of a chaotic flow column or thin surface film.

The invention furthermore relates to a device for treating liquids, inparticular dialysis liquids, for the purpose of sterilization andelimination of harmful substances contained therein. The devicecomprises a UV radiator and a case surrounding the UV radiator, whereinan additional internal case surrounding the UV radiator is alsoprovided, which is designed to have openings at the top for allowing theliquid to flow from the outside to the inside, such that the liquidflows through the openings and onto the surface of the UV radiator toform a thin flow film thereon.

This object is solved above all with the following features:

-   1. Killing or inactivating of living micro-organisms and funguses in    flowing water or aqueous solutions.-   2. Elimination of pyrogenic agents (endotoxins and exotoxins) in    flowing water or aqueous solutions.-   3. Elimination of pesticides, herbicides and fungicides in flowing    water or aqueous solutions.-   4. Enriching of the dialysis liquid with oxygen to help boost the    vitality of the dialysis patient during the dialysis treatment.

A device in which the following process sequences take place is requiredto achieve this goal:

The generating of ⁻OH radicals is initiated and maintained through thecombination of selected UV wavelengths and/or an integrated agitatingmechanism, preferably an ultrasound generator, wherein sufficient ⁻OHradicals are generated. These ⁻OH radicals are then distributed withsufficient uniformity in the liquid volume to ensure a high impactprobability between ⁻OH radicals and endotoxins and/or exotoxins,wherein this is ensured under static and dynamic conditions with a flowrate of a few ml/min to at least 10,000 ml/min.

The device according to the invention essentially can comprise one orseveral hollow bodies through which the aqueous solution to be treatedflows. It can be arranged outside of an apparatus or can be installed inan apparatus or can even form an integral part of an apparatus.

It is essential for the device according to the invention that at leastone UV radiator is installed in the hollow body, wherein the radiator orradiators emits (emit) a suitable combination of at least twowavelengths from the spectrum 170 nm to 260 nm.

It is furthermore essential to have a chaotic flow of the liquid in thehollow body, around the UV radiator(s). This chaotic flow is preferablygenerated with an integrated ultrasound generator (frequency >18 kHz).

This ultrasound generator functions as a type of agitating mechanism aswell as to produce H₂O₂. The UV radiator(s) in combination with anultrasound generator emits (emit) at least one wavelength from thespectrum 170 to 260 nm.

Furthermore essential is a specific flow course for the medium to betreated inside the hollow body, relative to the radiator or theradiators, that is to say in a relatively thin layer on the glasssurface of the UV radiator. The layer thickness of the aqueous solutionto be cleaned depends on the turbulence, the contoured surface of the UVradiator and the chaos created in the liquid.

Also essential are the following parameters, which can be in relation toeach other:

The hollow body diameter, the radiator tube diameter, the surfacecontour of the tube that is used, the inflow angle, the number ofradiators, the outside surface contour of the protective tube for theradiator or the radiator screening tubes used, the UV wavelength, theradiation output, the radiation density, the dwell time for the mediumto be sterilized, and the chaos generated in the aqueous solution in theradiated space.

Furthermore essential is a device installed inside the hollow body,which generates ⁻OH radicals and/or ozone and distributes these securelyand uniformly in the flowing aqueous solution.

Also important is that the aqueous solution to be cleaned containsphysically dissolved oxygen or that a device is present which feedsoxygen to the inside and/or into the flow chamber and obtains thisoxygen either from the environmental air or oxygen supply containers—oreven from the water itself.

The hollow body is provided with at least one inlet and at least oneoutlet for aqueous solutions. The openings can be at the bottom and/orat the top and can be installed either centered and/or tangentiallyaligned.

For the sterilization, the removal of endotoxins and the elimination ofthe hydrocarbons and/or aqueous solutions, the standard hose connectionand/or tube connection is separated and the device according to theinvention is then inserted as flow element with the aid of suitablecouplings.

Depending on the tube diameter, the contour of the inside surface of thetube used, the inflow angle, the number of radiators, the outsidesurface of the radiator(s) used, the UV ray wavelength that is used, theradiation output, the radiation density, the chaotic state of the liquidmolecules and the dwell time of the medium to be sterilized inside thetube, sterilization is securely achieved with a liquid throughputranging from a few ml/min (static) to at least 10,000 ml/min when usingthe device according to the invention.

The invention is based on the production and secure distribution of ⁻OHradicals and/or ozone in water or aqueous solutions, from which thegerms, pyrogenic agents (endotoxins, exotoxins) and hydrocarbons(fertilizers, pesticides, fungicides, herbicides) are removed. Thefollowing features are critical for this:

-   1. One or several UV burners emitting a specific wavelength or a    suitable combination of at least one wavelength within the limit    values of between 170 nm and 260 nm;-   2. A device for generating ⁻OH radicals and/or ozone inside the    hollow body, in the aqueous liquid to be treated;-   3. A flow guidance which ensures that all regions of the liquid come    in contact with OH radicals and/or-   4. A suitable device which securely distributes the generated ⁻OH    radicals in the flowing aqueous solution.

Possible embodiments are:

-   To 1: It is essential to have a combination of at least one UV    wavelength within the limit values between 170 nm and 260 nm and a    device on the inside of the case that ensures a turbulent flow and    chaos in the aqueous solution to be cleaned.

To 1 and 2:

-   -   The following physical chemical reaction is triggered and        maintained in the aqueous solution to be treated as a result of        the correct selection of the wavelengths, the liquid guidance        and the oxygen partial pressure in the water or the aqueous        solution:        Reaction I:    -   O₂+hv->0+O    -   O₂+O->O₃        Reaction II:    -   O₃+hv->O₂+O    -   O+H₂O->H₂O₂        Reaction III: H₂O₂+hv->OH+⁻OH        Reaction IV: endotoxins+⁻OH        →H₂O+CO₂+decomposition products

To 2:glucose oxidase+glucose+oxygen→gluconic acid+hydrogen peroxide

To 2:

-   -   Generating ⁻OH radicals from H₂O with a suitable UV wavelength        →H₂O+hv H+⁻OH

To 4 and 2:

-   -   Hydrogen peroxide and/or peroxide acetic acid is introduced        finely dosed into the liquid flow.

To 3:

The absorption in water of at least one of the UV wavelengths from thespectrum 170 nm to 260 nm is very high. To ensure that the completeliquid flow is confronted sufficiently with ⁻OH radicals, a flowguidance is necessary which ensures that the layer thickness for thewater or the aqueous solution to be treated does not exceed the depth atwhich the UV rays used with the aforementioned wavelength range canpenetrate in water or an aqueous liquid and/or a geometry is necessarythat ensures a secure distribution of the generated ⁻OH radicals.

And/or an agitating mechanism that ensure chaos in the aqueous solution.

To 4:

The absorption in water of at least one of the UV wavelengths from thespectrum 170 nm to 260 nm is very high. To ensure that the completeliquid flow is confronted sufficiently with ⁻OH radicals, it must beensured that at least one of the wavelengths from the spectrum 170 nm to260 nm, required for generating ⁻OH radicals, sweeps over the completeflow of liquid. According to the invention, this is achieved bystructuring the UV burner surface around which the liquid flows, or itsprotective tube, in the manner of stalactites or stalagmites. Thesurface can also be provided with rotation-symmetrical raised areas.Finally, it is possible to provide an agitating mechanism that ensureschaotic conditions in the aqueous solution.

To 5:

As a result of a suitable correlation of the following features: tubediameter, inside surface contour of the tube used, inflow angle, numberof radiators, outside surface of the radiator(s) used, UV wavelength,radiation output, radiation density, dwell time of the medium to besterilized in the tube and the chaos created therein, sterility and thestate of being free of endotoxins can be securely achieved with aflow-through rate between 0 ml/mn (static) and at least 10,000 ml/min.

The above-described device for creating sterile and endotoxin-free wateror aqueous solutions is particularly suitable for ensuring a more secureenvironment for patients and personnel during a haemodialysis treatment.That is to say, the haemodialysis treatment as described in thefollowing positions can be carried out with higher safety by thetreatment specialist while also being more effective and cheaper.

1. Online Dialysis Method:

During the realization of specific haemodialysis treatments, aconsiderably higher amount of liquid (substitute) is withdrawn from thepatient than can be continuously replenished from the patient's liquidpotential. The online dialysis has been and in part still is carried outwith the aid of substitute liquids purchased in bags and supplied to thepatient via compensation devices. In the process, a portion of thedialysis liquid produced by the dialysis machine is cleaned with the aidof sterile filters, such that it can be used as substitute, a processthat is very expensive. In addition, the substitute is produced fromnon-sterile dialysis liquid containing pyrogenic agents andendotoxins-/exotoxins. It means that the patient's safety is ensuredonly if all capillaries of the sterile filter used are withoutmicro-leaks.

2. Safety of the Patient:

The patient is subjected to considerable stress during the dialysistreatment as a result of the non-sterile dialysis liquid. Furthermore,the Venturi principle is used with nearly all dialysis machines on themarket for de-gassing the dialysis liquid with the effluent-water flow,the dialysate. In the process, a retrograde germ development can occurin the dialysis liquid. Sterile filters have a relatively short servicelife of approximately 200 h of dialysis operation. That is to say, thesterile filter must be replaced at least every two months. No indicatoris available at this time to indicate the depletion of the filter. Thisresults in a monitoring problem and additionally represents a dangersource during the filter replacement because the micro-organisms to beeliminated are not killed but accumulate inside the filter. For thatreason, the filter also seems to contribute to the generating ofmulti-resistant germs. Not least, micro-leaks can also develop as aresult of capillary breaks and can function as passages formicro-organisms and thus can represent an enormous danger to thepatient.

3. Danger to the Personnel:

For cost reasons, sterile filters are presently used only in front ofthe dialysis machine if they are used at all. It means that the dialysismachine is unprotected in the region for the dialysis liquid as well asin the effluent water region (dialysate). The dialysis machine thusoffers optimum growth conditions for any germs that enter. Theaccumulation of germs represent a considerable source of danger to thetechnical personnel. The filter replacement can also be a source ofdanger.

4. Environmental Protection and Hygiene:

So far, used dialysis liquid, the dialysate, has been released into thewaste-water systems without being cleaned. As a result of theconsiderable protein deposits in the waste-water pipe system, thisrepresented a fundamental problem for dialysis operators. These depositsform an excellent nutrient medium for all micro-organisms and areparticularly critical if highly infectious (hepatitis, HIV, etc.)dialysis patients are treated.

Remedial Actions According to the Invention:

First of all, the online dialysis can be realized more securely in thatthe substitute is produced from already sterile dialysis liquid, whichis then sterilized again and depleted of endotoxins. It becomes evensafer in that the micro-organisms are not raised to a different matrix,but are killed and their fragments essentially oxidized to H₂O and CO₂.In addition, no micro-leak can develop due to the breakage of filtercapillaries.

The permeate, the dialysis liquid, the dialysate, as well as thesubstitution solution are sterilized and cleaned of endotoxins, thusprecluding the dangers listed in the following:

-   a) Stress to the patient caused by non-sterile and endotoxin-loaded    dialysate;-   b) Retrograde germ development during the de-gassing of the dialysis    liquid while the used dialysis liquid (dialysate) is sterilized;-   c) No development of multi-resistant germs because all    micro-organisms are killed and their fragments are essentially    oxidized to H₂O and CO₂.

The permeate, the dialysis liquid, the dialysate, as well as thesubstitution solution are sterilized and cleaned of endotoxins, thusprecluding the dangers described in the following and achieving theadvantages listed below:

-   a) A retrograde germ development is impossible during the de-gassing    of the dialysis liquid because the used dialysis liquid (dialysate)    is sterilized, thus precluding the risk of contamination and the    danger of infection to the service technician.-   b) The considerably lower number of service intervals (12,000 h or    approximately 4.5 years dialysis operation) reduces the operating    time and the danger of secondary contamination.-   c) The efficiency can be monitored through reading of the indicator.-   d) No special solid-waste disposal of a filter loaded with    micro-organisms is required since the micro-organisms are killed.-   e) There is no longer any contamination caused by deposits etc,    something that basically cannot be avoided when liquid flows through    pipes. According to the invention a self-cleaning system is created    as a result of the ultrasound agitating mechanism.

The invention is explained in the following with the aid of examples andthe drawing, showing in:

FIG. 1 A cross-sectional view through a device according to theinvention.

FIG. 2 A corresponding cross-sectional view of a modified embodiment ofthe device according to the invention.

FIG. 3 A modified embodiment of the device according to the invention.

The embodiments shown in FIGS. 1 to 3 essentially have arotation-symmetrical design, wherein the individual case parts are madeof glass.

Reference number 10 refers to a cylindrical outer case into which theliquid to be treated is fed from below at point 11. The liquid can bepumped in with the aid of a pump and throttle valve, so that a specificvolume per time unit flows into the case 10. A liquid level 11 thenadjusts in the top region of case 10.

The cylindrical case 10 encloses an additional cylindrical case 40 onthe inside which is tapered in the lower region and is connected to aline extending out from the case 10 at a sealed location. In the upperregion, the internal cylinder 40 is provided with openings 41 at thesame height, wherein FIG. 1 shows two opposite arranged openings 41.These openings or holes can be slot-shaped and ensure that the level 11adjusts for the aqueous liquid inside the cylinder 10. At point 12, anarrow indicates how this liquid enters the inside space of cylinder 40and, in the process, forms a relatively thin surface layer on theoutside of a UV radiator casing. The liquid runs down on the case 20 andleaves the case at point 14 to flow via the above-mentioned pipe atpoint 15 into a catch basin.

The external case 10 is provided with a connecting passage at point 30,which allows the environmental air to enter the inside space of thecontainer 10, so that the oxygen in the air comes in contact with theliquid to be treated. For the embodiment shown herein, the environmentalair flows through the opening 30 into the container 10. For onepreferred embodiment, oxygen can be supplied instead.

Reference 21 finally refers to the UV radiator mount which is suppliedon the one hand with electrical energy while on the other hand it alsofunctions as mechanical holding device for the cylinders 10 and 40.

The liquid to be treated flows at 11 into the case 10 and finally formsa relatively thin layer or a film 13 on the surface of the UV radiator20. If the UV radiator is turned on, this film is exposed to therespective radiation. As a result of the relatively thin flow film, theliquid flow can be treated uniformly the UV radiator 20, using thewavelengths in question, so as to achieve the desired effect whichinvolves the generating of OH⁻ radicals with the aid of physicallydissolved oxygen or, as previously described, in the case of liquidsthat do not contain physically dissolved oxygen.

FIG. 2 shows a modified embodiment of the device according to theinvention where the outside contour 21 of the UV radiator 20 is designedsuch that the flowing liquid must cover a relatively long distanceduring which it is subjected to intensive radiation, in particular aradiation having the wavelength of 185 nm. This radiation affects theliquid 1 only over a short distance from the UV radiator surface sinceabsorption processes occur with higher thicknesses of the liquid filmand counteract the generating of OH— radicals. This effect of the largerUV radiator surface and/or the longer distance traveled by the liquidcan be further increased by installing obstacles in the flow path whichcreate turbulences in the liquid.

Within the framework of the present invention, devices of the type asshown in FIGS. 1 and 2 can also be installed one behind the other, sothat the desired treatment of the liquid can occur over severalsuccessive stages.

The inside wall of the outer container furthermore can conceivably havea non-cylindrical surface, e.g. a surface that corresponds to thesurface 21 of the UV radiator, so that the liquid must flow throughrelatively narrow flow passages. An easy to realize shape of this typewould be a helical or screw-type surface for the UV radiator 20 and amatching but slightly larger inside surface for the case 40.

It is furthermore possible within the framework of the present inventionto reverse the flow direction of the liquid, shown in FIGS. 1 and 2, sothat the liquid column flows from the bottom toward the top along theburner case.

FIG. 3 shows several ultrasound transmitters 50 on the side wall or inthe lower region of the case 10. However, a single ultrasound rod thatextends parallel to the UV burner 20 could also be used.

1. A device for the treatment of liquids, in particular dialysis liquids for the purpose of sterilization and elimination of harmful substances contained therein, said device comprising a UV radiator and a case surrounding the UV radiator, characterized in that an additional inside case (4) that surrounds the UV radiator (20) is arranged inside the case (10), that the inside case (40) is designed to have openings (41) at the top for allowing the liquid to flow from the outside via the openings (41) to the inside to be guided onto the surface of the UV radiator (20), such that a thin flow film (13) forms thereon and that an ultrasound probe is provided for generating and maintaining a chaotic flow along the UV burner or the UV burners and for producing H₂O.
 2. A device for treating liquids, in particular dialysis liquids for the purpose of sterilization and elimination of harmful substances contained therein, said device comprising a UV radiator and a case surrounding the UV radiator, characterized in that an additional inside case (40) that surrounds the UV radiator (20) is arranged inside the case (10), that the inside case (40) is designed to have openings (41) at the top for allowing the liquid to flow from the outside via the openings (41) to the inside to be guided onto the surface of the UV radiator (20), such that a thin flow film (13) forms thereon.
 3. The device with ultrasound probe for generating and maintaining a chaotic flow along the UV burner or the UV burners and for producing H₂O₂.
 4. The device according to claim 2, characterized in that the surface of the UV radiator (20) is a surface (21) that is enlarged past the standard inside jacket surface.
 5. The device according to claim 1, characterized in that it is arranged in a liquid dialysis flow circulation for a haemodialysis machine. 